(A) Safeguards. All openings, excavations and obstructions shall be properly and substantially barricaded and railed off, and at night shall be provided with approved warning lights. Warning lights perpendicular to the flow of traffic shall not be more than three feet apart, and parallel to the flow of traffic not over 15 feet apart.
(B) Shoring excavations. All openings and excavations shall be properly and substantially sheeted and braced as a safeguard to workers and to prevent cave-ins or washouts which would tend to injure the thoroughfare or sub-surface structure of the street.
Penalty, see § 96.99